Music boxes for playing music are well known in the art. One such music box includes a plurality of vibration valves, star wheels provided with claws for plucking each of the vibration valves, and stoppers corresponding to the star wheels. The vibration valves correspond to different pitches and, when plucked by a claw on a star wheel, produce sound at the corresponding pitch. By providing this music box with a mechanism capable of selectively plucking the vibration valves, the music box can play any music. According to the technology of this music box, the star wheel rotates upon the disengagement of the corresponding stopper therefrom and is brought into engagement with a sun wheel. In this condition, the claws on the star wheels can be made to pluck desired vibration valves to produce arbitrary sounds. The rotational speed of the motor is changed based on the tempo of the music.